Indications for and clinical procedures resulting from magnetic resonance imaging of the knee in older patients: Are we choosing wisely?

OBJECTIVE: To analyze the indications for and clinical procedures resulting from knee magnetic resonance imaging (MRI) in older patients.
DESIGN: We retrospectively analyzed 215 medical records of patients 50 years of age and older who had undergone a unilateral knee MRI in 2009.
SETTING: Centre hospitalier universitaire de Sherbrooke in Quebec. PARTICIPANTS: Patients 50 years of age and older who underwent a knee MRI in 2009. MAIN OUTCOME MEASURES: The main outcome measure was an invasive procedure in the same knee that underwent an MRI. Medical charts were reviewed up to 2014 for patient characteristics, MRI indication, ordering physician specialty, radiography before MRI, MRI findings, and clinical procedures resulting from the MRI.
RESULTS: The patients' mean (SD) age was 60.6 (7.5) years. The main MRI indications were meniscopathy (148 [68.8%]) and chronic pain (92 [42.8%]). The main MRI findings were osteoarthritis (OA) (185 [86.0%]) and meniscal lesions (170 [79.1%]). Only 82 (38.1%) patients had a plain radiograph in the 24 months preceding the MRI, usually without a standing anteroposterior view. Findings on pre-MRI radiography (n = 201) demonstrated OA in 144 (71.6%) patients. Overall, 87 (40.5%) patients were seen by an orthopedic surgeon and 27 (31.0%) of these patients underwent an invasive intervention. Among the 81 patients with moderate to severe OA on MRI, 36 (44.4%) had radiographic evidence of moderate to severe OA and only 3 (3.7%) underwent arthroscopic meniscectomy.
CONCLUSION: Our study reproduces the known association between OA and degenerative meniscal changes in older patients. We have found a surprising underuse of the standing anteroposterior view on radiography. Most patients in our cohort could have been appropriately diagnosed and treated based on such radiographic information, as demonstrated by pre-MRI findings, thus avoiding the MRI and subsequent evaluation by an orthopedic surgeon. Meniscectomy was rarely performed, particularly in patients with advanced OA. Educational and pragmatic measures must be emphasized to encourage the use of radiography and to limit the inappropriate use of MRI, a costly technique. Copyright© the College of Family Physicians of Canada.